CZ285298A3 - Crosslinkable water-soluble copolymers, process of their preparation and their use - Google Patents

Abstract

The invention concerns water-soluble cross-linkable copolymers having a molecular weight of </= 500000 and comprising: a) between 20 and 95 wt.% sulphonic-acid- or sulphonate-group-containing monomer units; b) between 4 and 80 wt.% N-methylol- or N-alkoxymethyl-group containing monomer units; and c) between 0.1 and 20 wt.% hydrophobic monomer units selected from the group comprising water-insoluble ethylenically unsaturated compounds and hydrophobic end groups of initiator radicals or regulator molecules, the portions in wt.% being relative to the total weight of the copolymer. The portion of sulphonic-acid- or sulphonate-group-containing monomer units can optionally be substituted by up to 50 wt.%, relative to the portion by weight of monomer units a), by carboxyl-group-containing monomer units d) or amide-group-containing monomer units e).

Description

Sepiatable copolymers, soluble in water, the method of their production and their use

Field of technology

The invention relates to water-soluble crosslinkable copolymers, the method of their production, as well as their use.

Current state of the art

Polymers with water-soluble ionic groups, so-called polyelectrolytes, have been known for a long time. These substances are polymers in which ionic groups, such as carboxylate groups or sulfonate groups, are firmly connected to the polymer backbone by a chemical bond. As a rule, this results in good solubility in water, as well as quite certain rheological properties, generally high viscosity in an aqueous environment.

These polyelectrolytes are produced by radical polymerization of ethylenically unsaturated compounds, soluble in water, which contain ionic groups. Examples of this are: acrylic acid, N-methylolacrylamide, acrylamido-2-methylpropanesulfonic acid (AMPS) and styrenesulfonic acid. In doing so, very high molecular weight polymers are created, whose aqueous solutions show a high viscosity.

EP-B 94898 (US-A 4 736 005) describes the production of very high molecular weight (molecular weight >1,000,000) terpolymers from 30 to 95% dimethylacrylamide (DMA). 0.1 to • · • · · · • ·

% of N-ethyl acrylamide (NMA) and 4 to 50% of acrylamidomethylpropane sulfonate (AMPS) and their use as Theological additives in oil extraction.

DE-A 2 618 898 (US-A 3 965 032) relates to colloidal dispersions which contain water-soluble or water-dispersible mixed polymer-polyelectrolytes with non-ionic hydrophobic units, for example methyl methacrylate, and ionic hydrophilic units, for example AMPS, the production of which takes place by polymerization in a solution in a water-miscible solvent. Specifically, mixed polymers are described, which contain a hydrophobic component in an excess of 2:1 to 6:1.

EP-A 629 650 (US-A 5 278 222) and EP-A 671 435 describe water-soluble and water-insoluble polymers of hydrophobic monomer units and 15 to 80% by weight, or 30 to 50% by weight of monomers, containing sulfonate groups, as an auxiliary spray agent for the spray drying of polymer dispersions.

Water-soluble polymers with high proportions of sulfonable water-soluble monomeric units, such as N-methylolacrylamide (NMA), would be of interest mainly in the form of their aqueous solutions as binders for coatings or adhesives. Another possible use would be as a dispersant in aqueous polymer dispersions. Water-soluble polymers with a high NMA content tend to have excessively high molecular weights with a correspondingly high viscosity of aqueous solutions. Water-soluble acrylic compounds, such as acrylic acid or N-methylolacrylamide as a cross-linking agent, have a tendency to very high degrees of polymerization, which, due to the resulting high viscosities, strongly affects the widespread • · · · use.

Another disadvantage of polyelectrolytes based on water-soluble monomers is that such polyelectrolytes are often incompatible with the polymer dispersion and that the aqueous solution of the polyelectrolytes separates as serum from the polymer dispersion.

• · ·

I · · · • · « » · ·

The essence of the invention

The basis of the invention is therefore to provide water-soluble and sieferable polyelectrolytes, which, despite the predominant proportion of water-soluble comonomers, have relatively low molecular weights, and which, when used as an additive to aqueous polymer dispersions, show a high affinity to the dispersed phase and surface-active properties.

Surprisingly, it was found that considerably lower molecular weights can be achieved when N-methylolacrylamide is copolymerized with acrylic compounds containing sulfonic acid groups or sulfonate groups. In addition, it was surprisingly found that the copolymerization of only small amounts of hydrophobic comonomers results in significantly lower surface tensions and lower viscosities.

The subject of the invention are water-soluble ziffifiable copolymers with a molecular weight of £500,000, containing

a) 20 to 95% by weight of monomer units containing sulfonic acid or sulfonate groups,

b) 4 to 80% by weight of monomer units containing an N-methylol group, or an N-alkylmethyl group,

c) 0.1 to 20% by weight of hydrophobic monomer units

I · · «

I · · · • · · · 1 • · ' • · · · • · · from the group of water-insoluble ethylenically unsaturated compounds and hydrophobic end groups of initiator residues or regulator molecules, where the proportions in % by weight refer to the total weight of the copolymer, and where the proportion of monomer units containing sulfonic acid groups or sulfonate groups can possibly be up to 50% by weight, based on the total weight proportion of monomer units a), substituted by monomer units d) containing a carboxyl group, or monomer units e) containing an amide group.

Preferred are water-soluble crosslinkable copolymers with a molecular weight of 500,000, containing

a) 30 to 87% by weight of monomer units, contain sulfonic acid groups or sulfonate groups,

b) 12 to 60% by weight of monomer units containing an N-methylol group or an N-alkylmethyl group, i.e. 1 to 10% by weight of hydrophobic monomer units from the group of water-insoluble ethylenically unsaturated compounds and hydrophobic end groups of initiator residues or regulator molecules, where the proportions in % by weight refer to the total weight of the copolymer.

Particularly preferred are water-soluble crosslinkable copolymers with a molecular weight of 500,000 containing

a) 70 to 87% by weight of monomer units containing sulfonic acid groups or sulfonate groups,

b) 12 to 25% by weight of monomer units, containing

an N-methylol group, or an N-alkoxymethyl group,

c) 1 to 5% by weight of hydrophobic monomer units from the group of water-insoluble ethylenically unsaturated compounds and hydrophobic end groups of initiator residues or regulator molecules, where the proportions in % by weight refer to the total weight of the copolymer.

Suitable units of monomer a) are, for example, water-soluble, radically polymerizable, ethylenically unsaturated compounds that contain sulfonic acid groups or sulfonate groups -SO3M, where Μ = Η, an alkali metal ion, an ammonium ion, or an alkaline earth metal ion. Preferred are 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrene sulfonic acid, sulfoalkyl ester of (meth)acrylic acid, sulfoalkyl ester of itaconic acid, preferably always with an alkyl group with 1 to 6 carbon atoms, vinyl sulfonic acid and its ammonium salts, salts with alkaline metals or salts with alkaline earth metals. 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrenesulfonic acid, acrylic acid sulfopropyl ester, itaconic acid sulfopropyl ester, vinyl sulfonic acid and its ammonium salts, sodium salts, potassium salts and calcium salts are particularly preferred.

Suitable units of monomer b) are, for example, water-soluble, radically polymerizable, ethylenically unsaturated compounds that contain N-methylol groups (-NH-CH2OH) and their ether derivatives (-NH-CH2OR, where R = alkyl with 1 to 6 carbon atoms ). Preferred are N-methylolacrylamide (NMA), N-methylol methacrylamide (NMMA), N-(isobutoxymethyl)-acrylamide (IBMA), N-(isobutoxymethyl)methacrylamide,

: i • · · ·

N-(n-butoxymethyl)acrylamide (NBMA). Particularly preferred are N-methylol acrylamide and N-(isobutoxymethyl) acrylamide.

Suitable units of monomer c) are radically (co-)polymerizable, ethylenically unsaturated compounds that are soluble in water at 23 °C less than 2% by weight, as well as hydrophobic end groups of initiator residues or regulator molecules with more than 8 carbon atoms. Acrylic or methacrylic acid esters with more than 3 carbon atoms, such as methyl methacrylate, vinyl aromatics such as styrene or vinyltoluene, olefins such as ethylene or propylene, vinyl halides such as vinyl chloride and vinyl esters of aliphatic carboxylic acids with more than 2 carbon atoms. The dodecyl residue from dodecyl mercaptan is preferred as the end group of regulator molecules. Particularly preferred are methyl methacrylate, styrene, vinyl propionate, isopropenyl acetate (1-methyl vinyl acetate), vinyl laurate, alpha-branched vinyl esters of monocarboxylic acids with 5 to 10 carbon atoms, such as VeoVa9^ or VeoValO^ .

Suitable monomers d) containing carboxyl groups are water-soluble radically polymerizable, ethylenically unsaturated compounds that contain carboxyl groups -COOM, where Μ = H, an alkali metal ion, an ammonium ion, or an alkaline earth metal ion. Acrylic acid, methacrylic acid, crotonic acid, itaconic acid are preferred. Suitable monomers e) containing an amide group are water-soluble, radically polymerizable, ethylenically unsaturated compounds that contain amide groups -CONH 2 . Acrylamide and methacrylamide are preferred, acrylamide is particularly preferred.

• 99

9

9·

9 ♦ 9 9 9 • * · · • · · · · · • · · · 99

The term water-soluble here generally means that the solubility in water at 23°C is at least 10% by weight. The molecular weight is given as the center of mass, determined by gel permeation (GPC) against a sodium polystyrene sulfonate standard.

The production of the copolymer according to the invention takes place preferably by radical polymerization in an aqueous solution at a reaction temperature preferably from 40 to 80 °C. Polymerization can take place by presenting all or individual components of the reaction mixture, or with partial presentation and additional dosing of all components or individual components of the reaction mixture, or by a dosing method without presentation.

Initiation takes place with the help of conventional water-soluble radical generators, which are preferably used in amounts of from 0.01 to 3.0% by weight, based on the total weight of the monomers. Examples are ammonium persulfate or potassium persulfate, hydrogen peroxide, potassium peroxodiphosphate, sodium peroxodiphosphate and ammonium peroxodiphosphate. Said radical initiators can also be combined in a known manner with 0.01 to 1.0% by weight of reducing agents, in which case the polymerisation can take place at lower temperatures. For example, alkaline formaldehyde sulfoxylates and ascorbic acid are suitable. In the case of redox initiation, one or both components of the catalyst redox components are preferably dosed during the polymerization.

The pH range required for polymerization, which is usually pH * 2.5, can be adjusted in a known manner with bases or conventional buffering salts such as phosphates or alkali metal carbonates. To adjust the molecular weight, commonly used regulators such as mercaptans, aldehydes and chlorinated hydrocarbons can be added during polymerization.

In one particularly preferred form of embodiment, part of the mixture of comonomers a), b), c), and optionally d) and e) is presented as an aqueous solution and the batch is heated to the reaction temperature. After reaching the reaction temperature, the radical starter and the remaining comonomer mixture are slowly added, always in an aqueous solution. After the end of dosing, the polymerization is completed by heating the handle to 85 to 95 °C.

In the most advantageous form of embodiment, at least part of comonomer a) containing sulfonate groups, usually 5 to 60% by weight, based on the total weight of comonomers a), as well as part of comonomers b), containing N-methylol functions, usually 5 to 60% by weight, based on to the total weight of comonomer a), is presented as an aqueous solution and the remaining amount of comonomer a) and b) is added.

The copolymers are preferably used in the form of their aqueous solutions. Depending on the application, the solids content is preferably adjusted to 15 to 25% by weight. Copolymers are suitable as a binder, or as an auxiliary rheological agent, for coating agents in the textile, paper and construction industry and as an adhesive in the textile, paper and construction industry. For example, the use of aqueous solutions of copolymers as an impregnation agent for non-woven fabrics has shown extremely good resistance to solvents and high resistance to wetness.

An advantageous field of application is also the use of copolymer solutions for the antistatic treatment of textiles, for example carpets and fleeces. For this, textiles can be impregnated with aqueous solutions. Another possibility of antistatic treatment consists in adding aqueous solutions of copolymers to dispersions of binders for joining textiles.

Due to the surprisingly low viscosities of aqueous copolymer solutions for polyelectrolytes and due to the additional surface-active properties induced by the hydrophobic units, the copolymers according to the invention are suitable for excellent stabilization of aqueous dispersions of polymers or aqueous emulsions of polymers.

Aqueous emulsions of polymers and aqueous dispersions of polymers are available by radical polymerization in a manner known to those skilled in the art. Examples of monomers useful for polymerization, alone or in a mixture, are vinyl esters of unsaturated carboxylic acids with 2 to 10 carbon atoms, such as vinyl acetate, vinyl laurate, vinyl ester of versatic acid; esters of methacrylic acid and acrylic acid with aliphatic alcohols having 1 to 8 carbon atoms, such as methyl methacrylate, ethyl acrylate, butyl acrylate. ethylhexyl acrylate; olefins such as ethylene, propylene; vinyl aromatics such as styrene; vinyl halides such as vinyl chloride.

The copolymers according to the invention can be presented or added in the form of aqueous solutions before polymerization or during polymerization as a protective colloid; usually in amounts from 1 to 15% by weight, based on the amount of monomers. Alternatively, the aqueous solution of the copolymer can be added in the specified amount to the polymer emulsion or to the polymer dispersion after the polymerization has ended. Another use is the use of aqueous solutions of copolymers according to the invention during spray drying of polymer dispersions as an auxiliary medium

blanket when spraying.

The following examples serve to further explain the invention.

Examples of embodiments of the invention

Comparative example 1:

Production of approximately 16% AMPS-NMA polymer solution.

Preparation of the metered monomer solution:

468 g of water were placed in a suitable dosing container and then the following substances were dissolved: 83.1 g of 25% NaOH solution, 0.866 g of mercaptopropionic acid (MPS), 159 g of 2-acrylamido-2-methylpropanesulfonic acid (AMPS) and 106 g of 45 % aqueous solution of N-methylolacrylamide (NMA).

1.24 kg of deionized water was gradually introduced into a laboratory reactor with a volume of 3 L, equipped with a leaf stirrer, reflux cooler and a suitable dosing device,

54.4 g of 25% NaOH solution, 0.866 g of MPS, 114 g of AMPS and 55.4 g of 45% aqueous NMA solution. The mixture was stirred and heated to 80 °C. Polymerization was started by adding a 2.2% aqueous solution of ammonium persulfate over 3 hours. 10 minutes after the beginning of the addition of APS, the monomer solution described above was added over a period of 2 hours. Then the polymerization was completed at 90 °C. After cooling, the pH of the solution was adjusted to 7.

The clear solution produced in this way had solids content

15.4%, pH value 7, viscosity 220 mPas (Brookfield, 20

• ·♦ · ·· ·· • ·

rpm) and an average molecular weight of 531,000 (GPC; against sodium polystyrene sulfonate standard), the surface tension of a 5% aqueous solution was about 67.5 mNm.

Comparative example 2:

Production of approximately 16% AMPS-NMA polymer solution.

Preparation of the metered monomer solution:

468 g of water were placed in a suitable dosing container and then the following substances were dissolved: 83.2 g of 25% NaOH solution, 0.866 g of mercaptopropionic acid (MPS), 184 g of 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) and 70 .9 g of a 45% aqueous solution of N-methylolacrylamide (NMA).

1.27 kg of deionized water was gradually introduced into a laboratory reactor with a volume of 3 L, equipped with a leaf stirrer, reflux cooler and a suitable dosing device,

55.5 g of a 25% NaOH solution, 0.866 g of mercaptopropionic acid, 114 g of solid 2-acrylamido-2-methylpropanesulfonic acid AMPS and 37 g of a 45% aqueous solution of N-methylolacrylamide NMA. The solution was stirred and heated to 80 °C. Polymerization was initiated by adding a 2.2% aqueous solution of APS ammonium persulfate over 3 hours. 10 minutes after the beginning of the addition of APS, the monomer solution described above was added over the course of 2 hours. Then the polymerization was completed at 90 °C. After cooling, the pH of the solution was adjusted to 7 using NaOH.

The clear solution produced in this way had solids content

15.8%, pH value 7, viscosity 82 mPas (Brookfield, 20 rpm} and average molecular weight 164,000 (GPC; against • · · · sodium polystyrene sulfonate standard), the surface tension of a 5% aqueous solution was about 65.1 mNm.

Example 1:

Production of approximately 16% AMPS-NMA-STY polymer solution.

Preparation of the metered monomer solution:

Place 459 g of water in a suitable dosing container and then dissolve the following substances: 81.5 g of 25% NaOH solution,

0.849 g MPS, 4.18 g styrene, 180 g AMPS and 69.5 g 45% NMA solution.

1.28 kg of deionized water, 54.4 g of 25% NaOH solution, 0.849 g of MPS, 112 g of AMPS, 36.2 g of 45% NMA solution and 2.62 g of styrene. The solution was stirred and heated to 80 °C. Polymerization was initiated by adding a 2.2% aqueous solution of APS over 3 hours. 10 minutes after the beginning of the addition of APS, the monomer solution described above was added over a period of 2 h. Then the polymerization was completed at 90 °C. After cooling, the pH of the solution was adjusted to pH = 7 using NaOH.

The clear solution produced in this way had solids content

15.8%, pH value 7, viscosity 48 mPas (Brookfield, 20 rpm) and average molecular weight 450,000 (GPC; against sodium polystyrene sulfonate standard), the surface tension of the 5% aqueous solution was about 61.6 mNm.

Example 2:

Production of approximately 16% solution of AMPS-NMA polymer with hydrophobic terminal dodecyl groups.

Preparation of the metered monomer solution:

455 g of water was placed in a suitable dosing container and then the following substances were dissolved: 80.9 g of 25% NaOH solution, 0.843 g of MPS, 179 g of AMPS and 68.9 g of 45% NMA solution.

Preparation of the dosed solution of the regulator:

5.39 g of dodecyl mercaptan were dissolved in 48.5 g of acetone in a suitable dosing container.

Into a laboratory reactor with a volume of 3 L, equipped with a leaf stirrer, a reflux condenser and a suitable dosing device, the following were successively introduced: 1.21 kg of deionized water, 53.9 g of 25% NaOH solution, 12.1 g of acetone, 0.843 g of MPS, 111 g of AMPS, 36 g of a 45% aqueous solution of NMA and 1.35 g of dodecyl mercaptan. The solution was stirred and heated to 80 °C. Polymerization was initiated by adding a 2.2% aqueous solution of APS over 3 hours. 10 minutes after the start of the addition of APS, the above-described metered solution of the monomer, as well as the metered solution of the regulator, were added over the course of 2 h. Then the polymerization was completed at 90 °C. After cooling, the pH of the solution was adjusted to pH = 7 using NaOH.

The clear solution thus produced had a solids content of 16.3%, a pH value of 7, a viscosity of 49.5 mPas (Brookfield, 20 rpm) and an average molecular weight of 148,000 (GPC; against sodium polystyrene sulfonate standard), surface tension

5% aqueous solution was about 63.9 mNm.

Example 3:

Production of approximately 16% AMPS-NMA-STY polymer solution.

Preparation of the metered monomer solution:

468 g of water was placed in a suitable dosing container and then the following substances were dissolved: 83.1 g of 25% NaOH solution, 0.866 g of MPS, 8.52 g of styrene, 173 g of AMPS and 70.8 g of 45% NMA solution.

Into a laboratory reactor with a volume of 3 L, equipped with a leaf stirrer, a reflux condenser and a suitable dosing device, the following were successively introduced: 1.27 kg of deionized water, 55.4 g of a 25% NaOH solution, 0.866 g of MPS, 111 g of AMPS,

36.9 g of 45% NMA solution and 5.33 g of styrene. The solution was stirred and heated to 80 °C. Polymerization was initiated by adding a 2.2% aqueous solution of APS over 3 hours. 10 minutes after the beginning of the addition of APS, the monomer solution described above was added over a period of 2 h. Then the polymerization was completed at 90 °C. After cooling, the pH of the solution was adjusted to pH = 7 using NaOH.

The clear solution produced in this way had a solids content of 15.8%, a pH value of 7, a viscosity of 54 mPas (Brookfield, 20 rpm) and an average molecular weight of 377,000 (GPC; against the sodium polystyrene sulfonate standard), a surface tension of 5% of the aqueous solution around 63.7 mNm.

The surface tension and viscosity of the polymer solutions of Examples 1 to 3 and Comparative Examples 1 and 2 are summarized • · ····

in Table 3. From the summary in Table 3, it is clearly seen that polyelectrolytes without hydrophobic groups (Comparative Examples 1 and 2) exhibit higher surface tensions and viscosities than polyelectrolytes with strongly hydrophobic groups (Examples 1 to 3).

Technical usability testing:

Testing the solutions of Example 1 as a binding agent for fibers:

The viscose fleece was soaked with the solution from example 1 using a scarf, wringed out and then dried for 3 minutes at 150°C (binder coating 29.5%). The strength of the fleece impregnated in this way was tested in the transverse direction. The test was carried out on a dry fleece, as well as on a fleece stored for 1 minute in water or isopropanol. To do this, three fleece strips with a length of 150 mm and a width of 15 mm were placed on top of each other and then tested together. The measuring conditions were as follows: clamp length 100 mm, clamp width 15 mm, measuring speed 100 mm/min. The highest tensile force was recorded as the measured value, i.e. the highest pull achieved during the measurement. The measurement results are summarized in Table 1:

Table 1

Dry Stored in H2O Stored in isopropanol

Top pull (N) 24.7

4.6

23.8

It is noteworthy that the strength after storage in isopropanol • · • · · ·

approximately corresponds to the strength of dry fleece.

Testing the solution from Example 1 for antistatic carpet treatment:

Needle felt, provided on the back side with 30% binder, was sprayed with 0.2%, or 0.5%, based on the amount of binder, of the solution from example 1 and dried for 3 minutes at 150°C.

On the carpet treated in this way, the half-time of electrostatic discharge was tested according to DIN VDE 0303, part 8, at different relative air humidity (10%, 30%, 50%). The applied voltage was 10 kV, the temperature during the measurement was 27 °C. The measurement results are summarized in Table 2:

Table 2

Humidity

10% 30% 50% Needle felt > 30 min. 1.5 min. 9 sec. Needle felt + 0.2% solution > 30 min. 12 sec. 8 sec. Needle felt -ΙΟ , 5% solution 15 minutes 9 sec. 1 sec.

The antistatic effect of the polymer according to the invention caused a clear decrease in the half-time of the electrostatic discharge.

• fc ···· • · • · · « ··

Table 3

Example Monomer component and) b) C) Surface tension Viscosity (% wt.) (% wt. ) (% wt.) (mNm) (mPass) Srv.l 21.0 NMA 79.0 AMPS _ _ _ 67.5 220.0 Compare 2 14.0 NMA 86.0 AMPS _ _ _ 66.1 82.0 1 13.7 NMA 84.4 AMPS 1.9 STY 61.6 48.0 2 13.7 NMA 84.3 AMPS 2.0 DDM 63.9 49.5 3 13.5 NMA 82.7 AMPS 3.8 STY 62.9 54.0

NMA = N-methylolacrylamide

AMPS = 2-acrylamido-2-methylpropanesulfonic acid

STY = styrene

DDM = dodecyl mercaptan ·· ·«*· «

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Claims (10)

Patents and claims Water-soluble, crosslinkable copolymers having a molecular weight of 500,000, comprising: a (a) 20 to 95% by weight of units of monomers containing sulphonic acid groups or sulphonate groups; (b) 4-80% by weight of monomer units containing an N-methylol group or an N-alkoxymethyl group; (c) 0.1 to 20% by weight of hydrophobic monomer units of the group of water-insoluble ethylenically unsaturated compounds and hydrophobic end groups of initiator residues or regulator molecules, the percentages by weight being based on the total weight of the copolymers; The sulfonic acid and / or sulfonate groups may optionally be up to 50% by weight, based on the total weight of monomer units a), substituted with carboxyl group-containing monomer d) or amide group-containing monomer e). 2. Water-soluble crosslinkable copolymers having a molecular weight of ž 500,000, containing (a) 30 to 87% by weight of monomer units containing sulphonic acid groups or sulphonate groups; (b) 12 to 60% by weight of units of monomers containing an N-methylol group or an N-alkoxymethyl group; c) 1 to 10% by weight of hydrophobic units of a monomer selected from the group of water-insoluble ethylenically unsaturated compounds, wherein the proportions in% by weight are based on the total weight of the copolymers. Copolymers according to claim 1 or 2, characterized in that they contain as monomer units a) one or more monomers selected from the group consisting of: 2-acrylamido-2-methylpropanesulfonic acid (AMPS), styrene sulfonic acid, sulfopropyl acrylic ester, itaconic sulfopropyl ester, vinyl sulfonic acid and its ammonium, sodium, potassium and calcium salts. Copolymers according to claims 1 to 3, characterized in that they comprise as monomer units b) N-methylolalkrylamide and / or N- (isobutoxymethyl) acrylamide. Copolymers according to claims 1 to 4, characterized in that they contain as monomer units a) one or more monomers from the group comprising esters of acrylic or methacrylic acid such as methyl methacrylate with more than 3 carbon atoms, vinylaromates such as styrene or vinyltoluene olefins such as ethylene or propylene, vinyl halides such as vinyl chloride, vinyl esters of aliphatic carboxylic acids having more than 2 carbon atoms, and hydrophobic end groups of initiator residues or regulator molecules each having more than 8 carbon atoms. 00 · · · • 0 0 0> 0 0 ·· 000 0 0 0 0 · 00 0 · Process for the production of copolymers according to claims 1 to 5, characterized in that the production is carried out by the free-radical polymerization of monomers a), b) and c) or d) and e) in aqueous solution at a reaction temperature of preferably 40 ° C to 80 ° C. by the initiation of water-soluble radical-forming substances, preferably at least a part of the comonomers a) containing sulfonate groups, generally 5 to 60% by weight, based on the total weight of the comonomers a), and a part of the N-methylol-functional comonomers b) % by weight, based on the total weight of comonomers a), is introduced as an aqueous solution and the remaining amount of comonomers a) and b) is added, and after reaching the polymerization temperature a free radical starter and the remaining comonomer mixture are added slowly in aqueous solution. Use of the copolymers according to claims 1 to 5, preferably in the form of their aqueous solutions, as binders or rheological auxiliaries for coating agents in the textile, paper and building industries and as adhesives in the textile, paper and building industries. Use of the copolymers according to claims 1 to 5, preferably in the form of their aqueous solutions, for antistatic treatment of textiles. Use of the copolymers according to claims 1 to 5, preferably in the form of their aqueous solutions, as protective colloids for stabilizing aqueous polymer dispersions and aqueous polymer emulsions. Use of the copolymers of claims 1 to 5 as a spray aid in spray drying of polymer dispersions.